The present invention relates generally to web printing presses and more particularly to a printing press roll having a non-contacting and disengageable motor device for rotating the roll during webbing-up.
To prepare for printing operations in a web offset lithographic printing press, the web end must first be fed over the various rolls and through the various nips in the press to the end of the press. This process is known as xe2x80x9cwebbing-up.xe2x80x9d Webbing-up may be performed in a variety of ways including manually, or by using automatic or semi-automatic web-up systems. As part of the webbing-up process an operator may manually rotate a roll to feed the web past the roll. Such manual feeding and roll rotation operations can be difficult and time-consuming, as well as present a safety hazard to the operator.
For example, former rolls below a former may be rotated by hand to assist in feeding the web through the nip area between the former rolls of a folder and into the lower portion of the folder. Because the web drives the rolls and due to the fact that the rolls are in close proximity to each other, there is a nip hazard present, i.e., there is a danger that the operator""s hand may become caught between the rolls and injured. Several guard designs have been employed in previous machines to protect the operator from the nip area. Many of these prior guard designs inhibit the operator from rotating the rolls to assist in webbing up.
Commonly-owned U.S. Pat. No. 5,605,267 describes a device for automatically advancing the end of a web over a former and into a folder unit in a printing press. A motor is used to rotate an endless belt which contacts the web and advances the web over the former and down through the former rolls. The motor also rotates the former rolls via belts to push the web through the former rolls and into the folder. A machined groove is required in one or both of the former rolls, which may result in marking on the printed product.
Prior devices may be complex and expensive.
The present invention provides a roll for a web printing press. The roll includes a cylindrical member configured for supporting a web, the cylindrical member being rotatable about an axis of rotation. Also included is a non-contacting and disengageable motor device disposed at the axis of rotation and configured for rotating the cylindrical member so as to advance the web over the cylindrical member during a webbing-up operation.
The cylindrical member may be movable axially and laterally and the motor device may be movable therewith. The motor device may be operable in conjunction with an automatic webbing-up system. Moreover, the motor device may be further configured for permitting the cylindrical member to rotate freely during a printing operation, or xe2x80x9cnormal operation,xe2x80x9d of the printing press.
The motor device may include an electric motor. The electric motor may be disposed at an end portion of the cylindrical member. Moreover, the electric motor may be housed within the cylindrical member.
The motor device may include a fluid motor. The fluid motor may be an air motor including a plurality of vanes attached to the cylindrical member and an air source configured for blowing air against the vanes so as to cause the cylindrical member to rotate. The vanes may be housed within the cylindrical member or within a housing disposed at an end of the cylindrical member. The air source may include an air outlet integrated in the shaft and disposed so as to blow air against the vanes. Moreover, the air source may include an air outlet disposed outside the cylindrical member so as to blow air against the vanes.
The roll may further include a control device for controlling a flow of air to the air motor, the control device being configured for stopping the flow of air to the air motor a predetermined time after a release of an operator air flow activation device.
The roll according to the present invention maybe a former roll.
The present invention also provides a web printing press including a cylindrical member configured for supporting a web, the cylindrical member being rotatable about an axis of rotation. A motor device is disposed at the axis of rotation and configured for rotating the cylindrical member so as to assist the advance of the web over the cylindrical member during a webbing-up operation.
The present invention also provides a method for rotating a roll in a web printing press during a webbing-up operation. The method includes: providing a motor device disposed at an axis of rotation of the roll and configured for rotating the roll so as to advance the web over the roll; and operating the motor device so as to rotate the roll.
The present invention provides a relatively inexpensive way of remotely rotating rolls, such as former rolls, during webbing-up, allowing a more complete roll/nip guard design.